1. Field of the Invention
The present invention relates to a pattern quality management chart, and in particular, to a chart which manages pattern quality for supplying a functional liquid for pattern formation to the surface of a substrate patterned by two regions having different affinities to the functional liquid to form a pattern.
The present invention relates to a pattern quality management method which manages pattern quality using the pattern quality management chart and a pattern formation method which forms a pattern while managing pattern quality.
2. Description of the Related Art
In the field of so-called printed electronics, in recent years, there has been attempted a shift from a subtractive method of etching an unnecessary portion to form a pattern to an additive method of forming a pattern of a necessary functional material using coating or printing and laminating a pattern as necessary. Various coating means or printing means have been appropriately used according to suitability, and of these, a noncontact printing method represented by an ink jet method has been attracting attention from the standpoint of not requiring to produce a printing original plate in advance, having excellent dynamic alignment suitability to substrate expansion and contraction accompanied by a thermal history during pattern formation, and coping with a large area process with high accuracy.
On the other hand, in a case where the ink jet method is used for general image printing, image quality largely depends on ejection accuracy of ink and drive accuracy of a carriage or sheet feeding. For this reason, an image process, a landing interference suppression control, and the like are performed to suppress image defects visually recognized for practical use, thereby compensating for image quality.
However, only with these methods, it is difficult to secure sufficient accuracy in giving an electrical function to conductive patterns or semiconductor patterns, such as wirings, electrodes, and antennas, in the field of printed electronics. JP1989-5095A (JP-S64-5095A) suggests a method which forms a conductive pattern using conductive ink through ink jet; however, in particular, when pattern micronization is promoted, pattern quality may be significantly deteriorated due to landing interference, such as gathering, movement, or deformation of a plurality of liquid droplets or liquid films, due to variations in the landing positions of the liquid droplets and the landing timing, and disconnection, short-circuiting, or the like of the conductive pattern may easily occur.
Accordingly, for example, JP4575725B suggests a method which creates a lyophilic/liquid repellent pattern of a lyophilic region and a liquid repellent pattern, that is, a pattern of regions different in surface energy on a substrate in advance and drops liquid droplets in the lyophilic region using an ink jet method, thereby performing patterning with high pattern quality to easily exhibit functionality, such as conductivity.
In the substrate on which patterning of the lyophilic region and the liquid repellent region is appropriately performed, it is known that, even though a coating method, such as spin coating or die coating, is used instead of the ink jet method, a conductive pattern having a certain level of quality is obtained, and for example, IEICE Technical Report, Electronic Devices, 112 (5), pp 25-29, 2012-04-11 discloses a method which spin-coats functional ink of silver nanoparticles on a lyophilic/liquid repellent pattern to form a conductive pattern.
In the method disclosed in IEICE Technical Report, Electronic Devices, 112 (5), pp 25-29, 2012-04-11, if the relationship of the surface energy of the lyophilic/liquid repellent pattern on the substrate and functional ink, and in particular, the contact angle of ink to each of the lyophilic region and the liquid repellent region is not in a given range, it is not possible to obtain objective pattern quality. Since the relationship of the surface energy changes due to various factors under the conditions of pattern formation, process management is important to improve quality and yield.
As the factors causing change in the relationship of the surface energy, for example, 1) an intra-lot difference and a change with time before and after coating of a material converted between a lyophilic property and a liquid repellent property with irradiation of ultraviolet rays, electron beams, heat rays, or the like for forming a lyophilic/liquid repellent pattern on a substrate, 2) an environment and a change with time after forming a lyophilic/liquid repellent pattern, 3) changes in physical properties (surface tension and the like) accompanied by an intra-lot difference of functional ink and lapse of time, 4) a light source state of ultraviolet rays, electron beams, or the like or a state of a heat source used for conversion between a lyophilic property and a liquid repellent property, 5) the temperatures of a substrate and functional ink, and the like are considered.
As one of the methods of confirming these factors, JP4325868B discloses a method which disposes a liquid repellent region for evaluation and a lyophilic region for evaluation adjacent to each other on an insulating substrate, prior to forming a wiring pattern, drops the same amount of functional ink in the central portion of each of the liquid repellent region for evaluation and the lyophilic region for evaluation using an ink jet method, and measures the liquid droplet diameter from above through image recognition.